Who's making ***** jokes? Now if I said those wheels look long dong you young people will probably think that is a ***** joke too. Well it might be, but you Viet Nam era folk know what I really mean.

heh heh i said p-p-*****....heh heh .... heh heh ...heh heh

 

Np on the info, glad to be able to contribute. I did forget to mention the speedo prob (thanks muscle). It's related to circumference (or girth to the ***** joke people). The speedo calculates off of tire revolutions, so with a different circumference the car travels a different distance per revolution. So though you now have less girth, you have more ***** (again, for the folks in the ***** gallery).

Sorry, couldn't resist.

Anyways, I used this trick "way back in the day". I picked up a '62 Fairlane (avoiding the four letter word that begins with F) around 1982. It had a blown (in the bad way) six cyl., so I dropped a 289 hypo w/ a 4 speed man. tranny in it. The factory 13" tires would just smoke through 1st & 2nd because of the low 6 cyl. gearing, and top speed was only about 75 MPH. Being on a low budget, I got some 15" tires and rims for the back instead of changing the differential gears and it became much more drivable. The speedo was wacked, but such was life on a budget.

Oh, back to the speedo, b/c you travel less distance per tire revolution, your speedo will show a higher MPH than you are actually traveling. The way I check this is when I see one of those digital speed trailer things that cops leave in places they want to control traffic (assuming they do that where you live), I go a steady speed and check it against the number on the speed trailer. Just remember that the difference is a percentage and not an integer. Meaning that if your speedo reads 80, and the trailer reads 70, then your actual speed is 87.5% of what your speedo reads (80/70 = .875), and not off by 10MPH. I'm sorry this is turning into math class, but it is important to know b/c in this example if your speedo was reading 40, your actual speed would be 35, not 30.

If you go by one of these things that shows you your speed, do this;

Write down the speed on your car's speedo and the letter "S" (for speedometer). The formula will refer to this number as simply "S".

Next write down the speed on the trailer (or other device that shows your actual speed) and the letter "A" (for actual speed) The formula will refer to this number as simply "A".

Get a calculator and enter "S" divided by "A". The number you get will be your multiplier. The formula will refer to this number simply as "M"

Now to calculate actual MPH the formula is "C" x "M" = "A"

Once again, apologies for going geek on ya.... Now where did I put my pocket protector.... Ah, there it is. Right next to my propeller beanie.

 

There's your ***** joke

 

Definitely not a placebo effect, word. Ever notice that racers all run on sub 15 lb wheels? When I switched to the traklites, I felt a biiiig difference. Rotational mass is hugely important, being as it creates a gyroscopic effect, as well as the fact that when you spin a perimeter weighted object at a high rate, centripital forces make it behave more like a 300 lb object would when static. Generally I have always believed that losing rotational weight is about 10x more important than losing static weight. The car should be a good bit more responsive in turns and braking as well since you are lowering the inertia that it takes to overcome the momentum of the spinning wheel and turn it in another direction. You lose some accelerative traction because it takes less effort to spin the wheels, but if you reign it in and keep them on the ground, the car will be faster. You will also feel a little more bounceback form the suspension, and maybe even hear different levels of roadnoise(besides the lack of buzz from your old stock kdwII's ).

 

Whitlightening: Great post! Oh. I don't really know how great it is because I don't follow the equations, but it sounds like you really know what you are talking about.

Story:

6th grade.

In the kitchen of our home.

I have my math book out and mom standing next to me.

There is this picture of a pizza and my mom and I were trying to do whatever equations they were wanting us to do with the pizza, but we couldn't figure it out.

I'm sure that my mother, at that time, regretted having a stupid son, and I'm sure that she blamed herself for having the stupid son...>LOL>

Post:

Yeah,,,the car feels like it has less traction too. I was thinking, at first, it was because I bought the wrong tires, but maybe it's because the car just wants to pull more.

Interesting thoughts, guys.

 

LOL